fix: some v3 branch fixes

[mustafar]

@JamesMessinger

Hi!

I was testing out the v3 branch as a dependency in my repo https://github.com/mustafar/parrot/ and ran into some bugs that I'm fixing here to the best of my understanding

1. I noticed that next() was not being invoked in some validate-request middleware; this was causing the middleware chain to stall.
2. I also saw that the isOpenApiRequest predicate was not guaranteed to be a bool.
3. basePath was being calculated in the setApi metadata middleware, but was not being set in context.api

Let me know if there's anything else I need to do to get this accepted and merged. Thanks!

[coveralls]

Pull Request Test Coverage Report for Build 289

• 10 of 40 (25.0%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.04%) to 41.122%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
lib/middleware/validate-request/validate-request-body.js	2	4	50.0%
lib/middleware/validate-request/validate-content-length.js	3	11	27.27%
lib/middleware/validate-request/validate-params.js	4	24	16.67%
<!--	Total:	10	40

Totals
Change from base Build 284:	-0.04%
Covered Lines:	784
Relevant Lines:	1717

---

💛 - Coveralls